Due to the increased awareness of the link between ultraviolet (UV) light and skin cancer, there has been a requirement for enhanced ultraviolet light protection in sunscreen products and in everyday skincare and cosmetics products.
There are two basic types of sunscreens, namely inorganic and organic UV absorbers or attenuators. Examples of inorganic sunscreens include metal oxides such as titanium dioxide, zinc oxide and iron oxide. A wide range of organic sunscreens have been used such as p-methoxy cinnamic acid esters, salicylic acid esters, p-amino benzoic acid esters, benzophenone derivatives, derivatives of dibenzoyl methane and esters of 2-cyanoacrylic acid.
The effectiveness of a sunscreen composition or end-use product can be determined by measuring the sun protection factor (SPF). High SPF values can be obtained by increasing the concentration of sunscreens in the formulation, however this will increase the cost, may lead to reduced aesthetic properties such as skin feel and appearance, and/or increased irritancy when applied to the skin.
Thus, there is a need for a material which when incorporated into a sunscreen composition or end-use product exhibits enhanced UV absorption or attenuation properties with inorganic and/or organic sunscreens. The enhancement of the UV absorption properties of inorganic sunscreens can be particularly challenging. There is also a need for such a material to be effective at low concentrations, and a requirement that the use thereof does not detrimentally affect the skin feel of the composition.
Polyvinylpyrrolidone (PVP) polymers and copolymers are well known and have been used in a variety of applications.